We have ruled out a large number of heavy atom compounds and are focusing on techniques to specifically target heavy atoms to our crystals through surface systeine mutants like Tma RuvB N32C and by binding mercury to the non-hydrolyzable ATP analog ATPyS. We are excited about the preliminary analysis of the ATPgS data which suggests that significant conformational changes are occuring in the crystal as the data does not merge with wild type but two different ATPyS-Hg crystal soaks merged well with each other. We plan to recollect the ATPyS-HG and a wildtype ATPyS control to solve the structure of the nucleotide bound crystal. We are also working on cocrystallization experiments to limit crystal mosaicity.